1. Field of the Invention
The invention relates to an apparatus for examining test bodies, in particular electronic subassemblies and electronic devices.
2. Background Art
Known from the prior art are various apparatuses for examining test bodies, in particular electronic subassemblies and electronic devices.
Furthermore, what are known as manipulators for positioning objects in space are known from the prior art. These manipulators make it possible to position an object with different degrees of freedom. The manipulators are constructed as industrial robots, hexapods or what are known as multi-axis table or portal systems. Furthermore, the manipulators are differentiated with respect to their mechanisms into serial manipulators, such as robots and mills, and parallel manipulators, such as hexapods. On account of their specific properties and parameters, the manipulators are suitable for different areas of application.
In the case of manipulators with serial mechanisms, a plurality of linear movement axes building on one another permit the positioning of an object in several dimensions. Here, each axis is provided for a movement in a defined direction. Furthermore, an additional use of rotary axes is known. An axis carries a further axis in each case, so that any desired positions in space can be set in and as a function of a number of axes.
Manipulators constructed as hexapods with parallel mechanisms are distinguished by an arrangement of six legs or axes, which are attached to a platform that can be moved freely in space. These legs permit positioning of the platform in space. For this purpose, the legs are constructed such that the length thereof can be varied or positions of endpoints of the legs that face away from the platform can be varied.
Irrespective of their design, it is necessary for all apparatuses that these permit predefined absolute and relative repetition accuracies. Here, absolute repetition accuracy is understood to mean the accuracy with which the object can be positioned. The relative repetition accuracy is understood to mean the deviation with which this position can be reproduced. Furthermore, irrespective of their design, the apparatuses have to be matched to a maximum mass and size of the object to be positioned and have a defined number of spatial degrees of freedom in which the object can be positioned. During the optimization of these parameters, i.e. the repetition accuracies, the maximum mass and size of the object and the number of spatial degrees of freedom, these behave contrarily. This means that the improvement of one of the parameters leads to restrictions of the other parameters.
WO 2009/121932 A2 discloses a rotation apparatus which comprises a rotating table having a rotation platform for radiographic, tomographic and laminographic examinations by means of radiation, wherein the rotation platform has a cut-out which is arranged around the axis of rotation. A rotor of the rotation platform or a holder has an XY positioning unit for lateral object positioning with respect to the axis of rotation. In addition, a parallel mechanism system for positioning inclined axes is provided.
Furthermore, US 2011/0181715 A1 discloses an apparatus for examining test bodies with a radiation source.